359 
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apy 1 



FREE HAND DRAWING 



BY 

MAX KUSHLAN 



THE BRANCH PUBLISHING COMPANY 



Free Hand Drawing 



and 



Designing 



BY 
MAX KUSHLAN 

S. B. Assoc, W,S. E. 



Author of 

Practtcai, Physics 



CHICAGO 

THE BRANCH PUBLISHING COMPANY 

1919 



<4f 



COPYRIGHT, 1919 

BY 

JOSEPH G. BRANCH 



©CI.A529212 



^\cm 



•>vO 



TABLE OF CONTENTS 

CHAPTER PAGE 

I Straight lyines 1 

II Curved Lines 8 

III Geometrical Bodies 16 

IV Perspective Drawing 23 

V Technical Illustrations 29 

VI Technical Sketching 38 

AND 

ENGINEERING DRAWING 

BY 

JOSEPH G. BRANCH 



FREE HAND DRAWING 



CHAPTER I. 

One of the greatest requirements of the modern en- 
gineer is to be able to make rapid neat sketches free- 
hand, i. e. without the use of any drafting instruments, 
but simply' by employing a well sharpened soft pencil 
and an eraser. There are many cases in the daily prac- 
tice of every engineer from the lowest to the highest 
ranks, when they are called upon to make a free-hand 
sketch of a job, and in some cases this rough sketch 
remains later the only available record of the condi- 
tion of the job before any changes took place. It is 
therefore important to have such sketches done as 
neatly and accurately as possible so that they would 
convey the correct idea to the draftsman or to the man 
who is to carry out the particular work represented 
by such sketches. 

There are two principal kinds of sketches employed 
in describing engineering work: the actual picture of 
the job, as it appears to the eye; and the ortho- 
graphic projection of the object in the three principal 
planes, but drawn roughly without the aid of instru- 
ments and not to correct scale. We will endeavor in 
the following chapters to cover the principles of both 
types of sketching, beginning with the simplest ob- 
jects first and then leading up to the free-hand draw- 
ing of more or less complicated parts of machinery. 
The text will be amply illustrated by suitable figures 
which are the actual reproduction of a complete course 
in free-hand drawing given in one of the leading tech- 
nical schools in this country, and the readers are ad- 
vised to follow up the exercises in the order suggested 



FREE HAND DRAWING 
PLATE 1. 



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F,y 3 45° Line 



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FREE HAND DRAWING 3 

in this course, so as to get the full benefit of the work. 
Each figure must be thoroughly mastered before the 
ntxit one is attempted as they gradually lead from one 
to the other. 

The first thing to learn about free-hand drawing is 
the correct method of looking at things. The eye must 
be trained to observe the size, shape and position of 
an object and its relation to the other objects around 
it. We must also be able to estimate distances and 
angles, not necessarily their correct values, but as they 
appear to our eye, which is usually out of proportion 
with the actual dimensions of the object. Before we 
learn to use the pencil we must therefore first learn to 
use our eyes and get the general habit of observation. 
It is a good plan to exercise in estimating sizes and 
distances of various simple objects such as tables, win- 
dows, books, wheels, etc. and then check these esti- 
mates with the correct dimensions as found by the 
foot-rule. It is surprising how such simple exercises 
help to train the eye until the student can tell the size 
and distance of an object within a small fraction of 
the actual value. 

Then the hand must be trained to a steady motion 
of the pencil by supporting it slightly with the small 
finger and moving it steadily in the direction desired. 
The student should avoid from the very start, the prac- 
tice of short, jerky movements of the pencil, indicat- 
ing that the hand is undecided to proceed with the 
line required. This usually gives a ragged line and 
leads to a great waste of time in trying to keep the 
proper alignment. The best method is to keep up a slow 
but steady motion, using the eye to guide the hand in 
the proper direction and then correcting with the 
rubber. The first line should be drawn faintly, then 
it should be corrected by touching up the various 
points that appear to be out of the proper direction, 
and then the line is to be strengthened by applying a 



FREE HAND DRAWING 
PLATE 2. 




^Jj 6 - Rectfkn^fe 




f:/<f 7, i^^Qi-e 




^f'sS- BjJM^hQl Tfi^hj/e 



FREE HAND DRAWING 5 

slight pressure on the pencil, so that the result is a 
smooth even line of uniform thickness. No instru- 
ments should be used except once in a great while for 
checking the work already drawn free-hand, and then 
the corrections should never be made by the aid of 
these instrument, but the work should be gone over 
free-hand until it checks very closely with the instru- 
ments. 

Referring to Plate I, Fig. 1 is the first and the 
most important element of freehand drawing, namely 
the horizontal straight line. 

This line should always be drawn from left to right, 
as indicated by the arrow, and the students must 
keep up this exercise until they are convinced that 
they can draw it perfectly without spending much 
time. It is advisable to check each line with a 
straight edge, after it is completed, and then to try 
to improve on it when drawing the next one. 

Fig. 2 is the vertical line drawn downward in the 
direction of the arrow. In this exercise the hand 
should be held in the same position as when using a 
knife in cutting a sheet of paper in the same direc- 
tion. It is a good idea to locate a few points or short 
dashes along the line before the line itself is drawn. 

In Fig. 3 a straight line is drawn in a direction of 
45 degrees from the horizontal. In order to accom- 
plish this the eye must be trained to estimate the an- 
gles between the line and the horizontal and vertical 
directions and to keep these angles as nearly equal as 
practicable. 

The exercise shown in Fig. 4 and 5 is to train the 
eye and hand to estimating divisions of a line. If the 
number of divisions are even, it is a good plan to be- 
gin by dividing the line into two equal portions, and 
when that Is accomplished, divide each half in the 
same manner. , In dividing a line into 5 equal parts, 
lay off a mark at a point between the second and 



6 FREE HAND DRAWING 

third portion, then divide the first part in halves, and 
the second part into three equal parts. If a line is to 
be divided in a certain proportion as indicated in Fig. 
5, divide the line into as many equal portions as are 
contained in the sum of the two numbers of the pro- 
portion required. Thus if a line is to be divided in 
the ration of 5 to 7, lay off 12 equal parts, and then 
take 5 parts for the first portion, and 7 parts for the 
second portion. 

This set of exercises must be thoroughly finished 
in every detail so that the eye and the hand w^ork in 
harmony and the lines and their divisions are correct 
within 5 per cent at least, before any attempt is made 
to take up the work of the next plate. 

The next step is to draw a correct rectangle, as 
shown in Fig. 6, Plate II, where the proper shading 
is added to give a better effect. The horizontal lines 
are drawn first as nearly parallel as could be done. 
Then one vertical line is drawn at right angles to the 
first two, and equal spaces are laid off on each hori- 
zontal line from their points of intersection with the 
vertical line; these points are connected by another 
vertical line, guiding it so that it is at right angles 
to the two horizontal sides and is parallel to the other 
vertical side. 

In drawing a square, as shown in Fig. 7, care 
should be taken to lay off the horizontal spaces equal 
to the vertical distance between the lines, since to 
the eye vertical lines always appear longer than hori- 
zontal lines of the same size, and the sides should be 
carefully checked by means of instruments until the 
student acquires the proper training in allowing for 
this optical illusion. 

The equlateral (equal-sided) triangle is drawn by 
first laying out a horizontal axis A B (see Fig 8, 
Plate II) and dividing line A B into halves at point 
D, and from D draw a vertical line at right angles to 



FREE HAND DRAV/ING 7 

A B. Try to locate on this vertical line a point C 
such that when connecting points A and B with point 
C. we will have lines AC and BC equal to AB. This 
will be rather difficult at first, but after a few trials 
the student will be able to find the correct point with- 
out any trouble. The lengths of the sides of the tri- 
angle can be checked roughly by making use of the 
pencil in laying off with the fingernail the size of 
AB from the end of the pencil then comparing this 
with the other two sides, carrying the pencil with 
the marking finger around to the different lines to be* 
measured. This furnishes a rough method for check- 
ing lengths and is frequently used by engineers in 
making sketches on the job. When the triangle is 
drawn correctly then the other two equal sides AC 
and BC (see Fig. 8) should be divided in halves, and 
each middle point should be connected with its op- 
posite vertex. The three lines drawn in such a man- 
ner from the vertices should meet in one common 
point as shown in the figure, making the whole 
arrangement perfectly symmetrical. 



CHAPTER IL 

Curved Lines. 

The ability to draw curved lines correctly seems 
at first to be a good deal more difficult than the 
straight-line work on rectilinear figures. This opin- 
ipn is, however, very far from the truth ; in fact, after 
a few trials the student will find that it is just the 
reverse : it is a good deal easier to draw curved lines, 
since our hand is more nearly adapted for a sweeping 
motion along a curved path, and in drawing a straight 
line we are^ constantly deviating from a curve by a 
strong exertion of our will. A good deal of the suc- 
cess in beginning the practice with curved lines de- 
pends upon the confidence of the student in his ability. 
to get good results; this will always produce a 
smoother curve due to the free and easy sweep of the 
determined hand, and will prevent a good deal of 
waste of time and energy at the very start. 

There are many ways of drawing a circle correctly 
without the aid of a compass, some of them being 
rather crude and primitive; but all of these methods 
are helpful in certain cases, and we will mention them 
all, leaving it to the student's judgment to decide 
which would be the best to use on different occasions. 

Everyone is familiar with the method of drawing 
circles by the help of some round object on hand, 
such as a coin of suitable size, a plate, or any round 
disk having a smooth edge. The disk is held firmly 
down on the paper with the left hand, the tips of the 
fingers being supported at a point near the center, 
and the pencil is held vertically in the right hand, 
which traces the circle, beginning from the top in a 
clockvv^ise direction, care being taken not to incline 



FREE HAND DRAWING 



the pencil so as to distort the curve and not to move 
the disk from its initial position. When the right 
hand reaches the part of the circle to the extreme 




A^. 9lCy^c/e 




left, then it is not advisable to try to finish the curve 
beyond the left arm, but it is much easier to change 
the position of the right hand to a point in front of the 
left arm and then resume the curve until the starting 
point is reached. The main disadvantages of this 



10 FREE HAND DRAWING 

method are the necessity of having a round object on 
hand of a size suitable for the circle to be drawn, and 
at best such a circle will not appear very smooth, 
due to the necessity of tracing it from point to point, 
and thus losing the correct direction of the curve in 
that process. Its advantages are the simplicity and 
saving in time, especially where only rough sketching 
is required. 

For circles of a relatively larger size, from 2 to 5 
inches in diameter, we can use the method of turning 
the paper about a point fixed by the right index finger, 
provided the paper is free to move and is not too 
large to make its motion clumsy or uneven. The 
pencil is firmly grasped between the right thumb and 
the forefinger, and the index is extended pressing the 
paper as a fixed pivot, about which the paper is slowly 
turned from right to left, or in a counterclockwise 
direction. The pencil resting lightly against the re- 
volving paper will describe a nearly perfect circle if 
the fingers are held in place during the complete rev- 
olution of the paper. 

It is evident that this is a very crude method, de- 
pending upon many unreliable factors, but it has the 
advantage of not requiring any special tools except 
a pencil and a piece of paper. 

Another way for drawing a little more perfect circle 
is to deliberately sweep the pencil in a clockwise di- 
rection describing a closed curve approaching a circle 
as nearly as possible, and then gradually smooth- 
ing out and correcting those portions of the curve 
that seem to be defective, until a nearly correct circle 
is drawn. 

This method requires some skill and a determined, 
swift movement of the hand, which could be acquired 
only by long and patient training of the hand and the 
eye. The main advantages of this method are the 
good results that are usually obtained, producing a 



FREE HAND DRAWING 



11 




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FiS^ /2 /^ect(xn^u /ah So/icf 




/t^, /3 -Pyt-oinjfcf 



1^ FREE HAND DRAWING 

smooth and almost perfect circle, and its independ- 
ence of any variable conditions that would tend to 
distort the directions of the curve. 

The most scientific way of drawing a circle is out- 
lined in Fig. 9, where we first draw two axes at right 
angles to one another; then the length of the radius 
of the circle is laid off as equal distances from the 
point of intersection of the axes in the four direc- 
tions. It might be of help to draw two more lines at 
45 degrees to the first ones, intersecting at the same 
point, and to lay off the length of the radius upon all 
these lines. The spacing is estimated by the eye and 
can be done very accurately after a few trials. Then 
the points thus laid off are connected with a smooth 
circular curve, and the whole circle is corrected so 
as to make as perfect a curve as could possibly be 
obtained without the use of instruments. The free 
use of the eraser is strongly advised for this work. 

In order to draw the ellipse we must first know the 
properties of that curve, so as to be able to check our 
work with the correct curve. The two axes at right 
angles to one another, as shown in Fig. 10, are the 
principal lines of the curve. The longer axis, which 
in this case is drawn horizontally, is termed the major 
axis of the ellipse, and the shorter vertical axis is 
known as the minor axis. If from the upper extrem- 
ity of the minor axis we are to lay off accurately the 
length of "I of the major axis, swinging this arc until 
it strikes the horizontal line, we will thus obtain two 
points on the horizontal line, inside of the ends of the 
major axis. These two points are called the foci 
of the ellipse. The correct ellipse is then to be 
constructed in such a manner that the sum of the 
distances from any point on the curve to the foci 
is equal in length to the major axis. This prin- 
ciple could be used for checking the freehand curve 
by means of a compass, until the student is able to 



FREE HAND DRAWING 



13 



draw the ellipse correctly. In drawing the ellipse 
without the aid of any instruments we lay off the 
major and minor axes accurately, estimating the 
lengths so as to make the figure perfectly symmetri- 
cal. This gives us four points on the curve, and these 
are then connected with the smooth curve, checking 
the outline by the eye until we obtain the correct 
elliptical shape. It might be of help to bear in mind 
that the portions of the ellipse near the extremities 









FIG 14. 



of the major axes are very nearly circular, while the 
portions near the extremities of the minor axes are 
nearly straight lines. 



14 FREE HAND DRAWING 

Drawing From Models. 

The principles outlined above will enable the stu- 
dent to make neat sketches of simple solid bodies, 
such as cylinders, rectangular solids, cubes, pyramids, 
cones, etc. In order to learn the appearance of these 
geometrical bodies from different angles it is advis- 
able to obtain some simple models of these bodies 
and devote some time in copying them in different 
positions and from different angles. At first it is 
advisable to draw these solids in their normal posi- 
tions, such as indicated by the Fig. 11, which is a 
freehand sketch of the cylinder. Fig. 12 being a view 
of the rectangular or oblong solid, and Fig. 13, which 
is a side view of a square pyramid. Especial attention 
should be given in shading the sides of these figures 
by either carefully noting their actual appearance in 
life, or by imagining a ray of light illuminating them 
at a certain angle. 

Referring to Fig. 11, it is important to remember 
that the top and bottom of the cylinder, although cir- 
cular in shape, appear to the eye as elliptical, so that 
in this case the top is drawn as a complete ellipse, 
having its major axis equal to the actual diameter, 
while the minor axis is made shorter, the amount of 
shortening depending upon the relative position 
of the observer and the body. The bottom is drawn 
as a half of an ellipse, equal in size to the one at the 
top. The light is assumed to come from the lower 
right hand corner, so that the left portion of the fig- 
ure is shaded, the degree of shading varying from 
heavy to light as we proceed towards the right. 

In Fig. 12, representing the rectangular solid, care 
should be taken to make all the edges as near parallel 
as practicable. In Fig. 13 the pyramid is placed in 
such a position that only two of its triangular sides 



FREE HAND DRAWING 15 

are in view, the slope of the lines at the bottom de- 
pending upon the angle at which the observer is 
placed in relation to the body. 

Fig. 14 is a combination of a cylinder (upright), 
and on the left a square pyramid lying flat on one of 
its sides, with its bottom exposed to view, and its top 
hidden behind the cylinder, and to the right we have 
a cube partially hidden behind the right edge of the 
cylinder. The student is advised to make this exer- 
cise by arranging the models in the same manner and 
drawing the figure without referring to the illustra- 
tion here shown, then comparing the result with Fig. 
14. Then the models are to be rem.oved and the same 
arrangement is to be drawn from mem.ory, including 
the shading. This will enable the student to grasp 
the idea of the true representation of objects as they 
appear to our eye, and will lay the foundation for the 
more advanced free hand sketching, either from life 
or from memory. It might be advisable to mention 
here that the beginner is warned to proceed with the 
above exercises very slowly and in their logical order 
outlined above, being careful not to begin the work 
of any new figure until the preceding exercise has 
been thoroughly mastered in every detail. 



CHAPTER III. 

Geometrical Bodies. 

The representation of geometrical bodies in space 
requires a good deal of skill which could be acquired 
only after a systematic course of study based upon 
careful observation of the appearance of objects in 
nature. As suggested in the previous chapter, the 
student is strongly advised to make use of constructed 
models in going over the following exercises. By 
rearranging these bodies in various positions with 
respect to one another and to the horizontal plane, we 
can produce as many combinations as we desire, thus 
making a practical study of the actual appearance of 
these bodies from different angles and with different 
shadings. 

Referring to the group of bodies shown in Fig. 15, 
we have here three geometrical bodies: — a cube, a 
cylinder and a triangular prism. The cylinder is 
shown standing upright with the cube tilted and lean- 
ing against the back part of the cylinder, towards the 
left, and the prism is shown in front of the cylinder 
lying flat on one of its sides at an angle, and one of 
its edges just touching the forward portion of the 
cylinder. 

In order to draw this position correctly with the 
least trouble, it is advisable to begin with the cylinder, 
since this is the central figure in the group. First 
draw the top of the cylinder as an ellipse, determining 
the correct ratio between the major and minor axes 
by the eye, remembering that the major axis (hori- 
zontal axis) is equal to the correct diameter of the 
circular top, while the vertical axis is the one that is 



FREE HAND DRAWING 17 

foreshortened. After sketching in very lightly the 
four extremeties of these axes and the other principal 
points on the curve, the ellipse is then drawn in 
heavier lines, forming a smooth and symmetrical 
curve. Then the edges of the cylinder are drawn as 
plain vertical lines, and both the top and the lateral 
surfaces are shaded towards the left, since the light in 
this case is shining from the lower right hand corner 
of the plate. (See Fig. 15). 

The next step is to draw the prism, beginning with 
the forward face in its correct relative position and 
without any shading since the light is shining right 
upon the surface. Then the face of the prism which 
is away from us is shown as a rhomboid with one side 
elongated and the other side shortened, since that 
would be its natural appearance to our eye. That side 
is shaded quite heavily, and its shadow is slightly indi- 
cated falling upon the forward left portion of the 
cylinder. 

The outline of the prism is now completed by fin- 
ishing the third side of the triangular end, which is 
shaded towards the left due to its inclination to the 
rays of light. 

The cube which is partially covered by the cylinder 
is then drawn, beginning with the face nearest to the 
cylinder, this face receiving the shadow thrown upon 
it by the cylinder. Then the bottom of the cube is 
drawn with two of its edges parallel to the corres- 
ponding edge upon the top of the front face, and the 
left edge of the bottom making the proper angle with 
these parallel edges. The bottom is heavily shaded, 
and so is the space between this bottom and the cylin- 
der since the rays of light do not reach into that por- 
tion of the group. The outline of the cube is finished 
by drawing the left face as a rectangle having all its 
sides parallel to the corresponding edges of the other 



18 



FREE HAND DRAWING 



face that has already been drawn. The left face of the 
cube is not shaded since it presents all of its surface 
to the light. - 

By carefully examining Fig. 15 the student will ob- 
serve that the shading is made according to certain 
definite principles which could easily be acquired by 
following out each portion of the figure with reference 




FIG. 15. 

to the source of light. It is also clear that the propor- 
tions of the bodies as shown in the drawing are very 
much distorted from their actual measurements since 
by observing an object from a certain angle we see 
some lines longer and other lines shorter than they 
actually exist in space. To illustrate this, let us 



FREE HAND DRAWING 19 

imagine that we are looking at a straight line placed 
vertically at a certain distance from us parellel with 
the vertical axis of our body. We then see it as a 
vertical line in its correct actual length. Now, if we 
were to tilt this line forward or backward, we will get 
the impression that this line is still vertical if we have 
not moved it to the right or left, but the line will 
appear to our eye a good deal shorter since due to the 
tilting the upper end of the line is vertically nearer to 
the lower end. By tilting the line more we see it 
getting shorter and shorter, until when we get the line 
in a position at right angles to our body, all we can 
see is the point of its nearest end, and if we look 
straight at the line we cannot tell whether it is a line 
or a single point. 

In the same manner we can look straight at a circle 
placed with its plane parallel to our body, and then 
we see it in its actual circular shape. But if we re- 
volve the circle about its horizontal diameter, we will 
get the impression of an ellipe, the major axis being 
equal to the horizontal diameter, and the minor axis 
being the vertical distance between its upper and 
lower edges. It is evident that the more we tilt the 
circle, the shorter will be the appearance of the ver- 
tical axis of the ellipse ; and if the circle is placed with 
its plane at right angles to our body, the circle will 
then give us the impression of a straight line equal 
in size to the diameter. 

From the above illustrations it is evident that the 
amount of distortion of an object as it appears to our 
eye bears a direct relation to the angle at which we 
observe it, and in each case the proper shortening or 
lengthening of the lines can be correctly determined 
by the analysis as outlined in the above two cases. 

This process, however, is rather tedious and requires 
a lot of valuable time, so that in this free-hand work 



20 



FREE HAND DRAWING 



the students are not expected to perform their work 
in such a manner. 

The easiest and quickest way is to get the proper 
amount of distortion from practical experience with 
models ; but the principles underlying the causes for 
such distorted proportions should always be kept in 
mind as a guide and a check to the practical execution 
of the work. 




FIG. 16. 

Fig, 16, representing another arrangement of a cube, 
a cylinder and a square pyramid, will furnish addi- 
tional suggestions for arranging the models and for 
proper shading. The students are advised here to 
carefully distinguish between the shades and shadows 
in these figures. By the shade of a body is meant the 
darkened portion of the surface of the body due to the 
more or less partial obstruction of that part from the 
direct rays of light. By the shadow is meant the 
darkness produced upon the surface of a body due to 



FREE HAND DRAWING 



21 



the obstruction from the rays of light by some other 
body placed in their path. Thus, in Fig. 16, the upper 
portion of the cylinder shows the shading, while the 




Fia 17, 

part near the bottom of the cylinder is the shadow cast 
upon the ground and upon the cylinder by the pyra- 
mid. Both the shades and shadows must be included 
in any complete freehand sketch to make it appear 



22 FREE HAND DRAWING 

more natural and true to the appearance of the same 
bodies in life. 

As an illustration of fine work in shades and 
shadows we have the free-hand sketch in Fig. 17 
showing the appearance of a cone, with two sections 
made in it, one parallel to its vertical axis resulting in 
the shape of a parabola, and the other section taken 
at an angle between the horizontal and vertical planes, 
giving the shape of a portion of an ellipse. The cone 
is here represented standing upright upon a table, the 
shadow of the cone falling to the right, partly upon 
the back wall, and partly upon the surface of the table. 
The source of light in this case seems to come from 
the lower left hand corner, so that the shading of the 
object, wall and portion of the table is heavier towards 
the upper right hand portion of the sketch. Attention 
is also called to the fact, that all the shading is done 
here by straight lines varying in density and in direc- 
tion according to the requirements, and the outline of 
the objects being produced by the shade lines them- 
selves meeting one another, as would be the case with 
the appearance of objects in nature. Such shading is 
very often made with the help of a straight edge, and 
gives excellent results if the available time allows such 
refinements. 



CHAPTER IV. 
Perspective Drawing. 

In order to represent objects exactly as they appear 
to our observing eyes we must take into account the 
peculiar optical illusion that distorts the proportions 
of the bodies when placed at an appreciable distance 
from the observer. In case the body is placed far 
from the eye it appears a good deal smaller than it 
actually is, the amount by which the size seems to be 
diminished being directly proportional to the distance 
between the object and the observer. Thus when a 
train moves away from the observer, the last car 
seems to get smaller as the train moves farther away, 
and when the car is twice as far from the observer 
than it was when he first looked at it, its size appears 
about one half of what it seemed to be at the first ob- 
servations. 

By looking at a long object that stretches quite a 
considerable distance directly in line of observation, 
the front portions of that object will appear -a good 
deal larger than the parts that are at the farther end. 
Such is the common experience with views of long 
buildings, streets, rows of trees, posts in line, and sim- 
ilar objects that are made up of similar parts arranged 
along definite straight lines. 

To illustrate the simplest case of this effect we have 
the sketch in Fig. 18 of a bookcase lying flat on the 
floor, away from the observer who is looking down 
upon it, but not directly over it. The front portion of 
the bookcase nearest to the observer is drawn a good 
deal larger than the rear end, and the sides are made 
to slope gradually from the larger to the smaller rect- 



24 



FREE HAND DRAWING 



mm 



I- 








m 



I I I I I I I I I I I I 



FREE HAND DRAWING 25 

angular shape. Following the same idea, the distance 
between the first shelf and the second one is shown 
proportionally greater than the distance between the 
second and the third shelf, etc. It is important to no- 
tice the widths of these shelfs are drawn unequal, get- 
ting gradually smaller as we go from the front view 
to the rear. All the other portions of the bookcase 
are drawn along the same lines which are not parallel 
but all slope towards some imaginary common point 
of intersection, which is known as the vanishing point 
of the picture. By holding this sketch at a distance 
from the eyes equal to about the length of the arm, 
the reader will observe that the impression given by 
this sketch is of an object having all its edges per- 
fectly parallel, although by examining it more closely 
we can see at once that they are far from being 
parallel. Such a method of representing solid bodies 
is known as Perspective drawing, and is used a great 
deal in many cases by engineers, artisans, mechanics 
and architects. 

The correct methods used in representing a simple 
object by means of perspective drawing is illustrated 
by Fig. 19, which shows the outline of a house drawn 
by the observer standing at the one of its corner at 
some distance and a little above it so that he could 
get the full view of the walls and the roof. In this 
case use is made of two vanishing points, marked A 
and B respectively. Each of these vanishing points is 
used for each of the two walls visible to the observer, 
since he gets two directions in which the lines of the 
object seem to converge into single points if they were 
continued far enough. All the parts of the building 
are drawn in the same manner getting smaller and 
nearer to one another as we go from the nearest cor- 
ner to the far ends of the building. s 

The sidewalks are represented in the same manner, 
so that by looking at Fig. 19 at a distance we get the 



26 



FREE HAND DRAWING 




FREE HAND DRAViJING 



27 



impression of the actual building as it appears to our 
eyes under similar circumstances. 

Fig. 20 illustrates the same principles of perspective 




applied to an object having several curved lines as 
well as straight edges. The portable blackboard 
shown here has rounded corners at the bottom pieces 



28 FREE HAND DRAWING 

of the supporting frame, also some rollers and 
curved iron rods to support the brackets and to stiffen 
the wooden frame. All these curves are drawn out of 
actual proportion, but in the correct ratio of the dis- 
tance of each point from the observer, the whole sys- 
tem of lines converging towards the single vanishing 
point A. This sketch is made still closer to actual ap- 
pearance by the shading of some portions of the frame 
and very light shading of the visible portion of the 
board itself. 

In drawing any object by the above method it is 
best to observe closely the apparent angle which the 
lines of the object make with one another, and then 
lightly sketch in these outlines, changing them until 
the correct vanishing point is finally located. Then 
the main outlines are marked off along these vanish- 
ing lines keeping all the vertical directions straight 
up and down and parallel, since in ordinary cases the 
vertical distances are not far enough to be represented 
at a distorted angle. The distances along any of the 
vanishing lines are then laid off in the proportion of 
the location of the points from the observer, the larg- 
est distance being directly in the front view, and the 
smallest distance being the last one near the vanish- 
ing point. This does not have to be made correct in 
such proportion, since it is only important to produce 
the general impression rather than make an exact 
layout, which could only be accomplished by means 
of drawing instruments and many computations. In 
ordinary cases the sketch is laid out roughly, aided 
only by the experience of the trained hand and the 
judgment of the eye. 



i|i|i| |i|M'i'ri'i'i'i I I B I I 



CHAPTER V. 

Technical Illustrations. 

In this course of free-hand drawing we have so far 
presented all the important theoretical elements neces- 
sary for the production of a correct sketch. Begin- 
ning with the simple exercises of the straight lines 
and elementary curves we have taken up the ques- 
tions of drawing solid objects, the rules for shading 
and the principal requirements for perspective draw- 
ing. These exercises will enable the student to make 
a neat and accurate sketch of a simple object. 

We will now endeavor to take up the practical appli- 
cations of the above principles so as to present a con- 
cise course in technical free-hand work used for mak- 
ing simple illustrations or rapid sketches of actual 
pieces of machinery or apparatus, taken in the field 
and used later for a more careful drawing to scale 
by means of instruments. 

In this work we can freely use the rule for making 
straight lines, since in case of practical drawing of 
this kind the straight edge is invariably used in one 
form or another. 

We will first discuss a few typical examples of more 
or less elaborate free-hand drawings that are to be 
used as technical illustrations rather than working 
sketches; or, in other words, we will study how to 
make a neat-looking free-hand drawing of some tech- 
nical appliance to be used for illustrating^ a cata- 
logue, an advertisement in a technical magazine or an 
engineering paper of any kind without giving any 
exact dimensions or details, but presenting z general 



30 



FREE HA.sTD DRAWING 



idea about the appearance or arrangement of the par- 
ticular part that we wish to describe. 

Such illustrations are often made purely from the 
imacrination or by memory without the aid of any 
TdeTs or drawings of .Ij kind^ But it - more 
common and advisable to have either fe object or a 
reduced model of the part to be illustrated in front 
of the sketching pad, so that the drawing xs made 
more accurate with the proper shading and the diflfer- 
Sit portions of the objects shown m their cor ect 
relative proportions. In case the object is not avail- 
able or is tJo large, and a model is too expen^ve or 
could not be obtained for any other reasons, the next 
best thing to do is to make use of a photograph show- 
ing severll views of the object to be represented. From 
thlse photographs we can form .a clear idea of the 
exact construction of the part in question and after 
ehmLating all the "--P-t-t details and ou lining 
the main features we can draw the object with its 
essential details so as to bring out more forcibly ce;^- 
tain parts which we wish to emphasize, and to elim- 
inate all the features which are of secondary import- 
ance and are liable to confuse the reader 

Referring to Fig. 21, we have here a sketch of a 
wooden pa^ttern ffr the main casting of. a dynamo- 
machine. This is drawn from the full-sized pattern 
Saced at such an angle that all the mam features of 
fhe pattern are well illustrated such as the circular 
rnagSec frame, the supporting plate, the two end 
Seces and the poles attached to the intenor portion 
S the frame. The drawing also shows the ocat - 
of the lines of splitting the pattern both horizontally 
and vertically, also the smaller details such as lugs, 

'TSintoS'the above sketch we first determine 
the axes of symmetry of the whole figure, which in 
tWs case are the axes of the ellipse representing the 



FREE HAND DRAWING 



31 



outer edge of the circular frame. These Unes are 
drawn in very light, the vertical axis being a vertical 
line, but the horizontal axis drawn inclined lower to 
the right, making an angle of 15°-20° to the horizontal 
line. Then the width of the framing is lad off hori- 
zontally at the top, and the two ellipses are drawn 
in according to the methods outlined in the previous 




FIG. 21. 
PATTERN OF DYNAMO. 

chapters. Only those portions of these ellipses are 
shown that are actually visible, but the outline could 
be made with ellipses complete in very light lines, 
and then the portions that are visible are gone over 
with firmer lines, while the invisible parts can be 
erased. 

The supporting plates (see Fig. 21) are then drawn 
by means of the rule and pencil, care being take to 



Sa FREE HAND DRAWING 

make the opposite edges nearly parallel or gradually 
and very slightly converging towards the background 
to give the correct perspective view. The end pieces 
of the framing are next drawn making one edge of the 
piece parallel to the corresponding edge of the sup- 
porting plate, and the other edge, placed at an angle of 
about 120° from the first one, which will give the im- 
pression to the eye of a right angle. 

In following up this sketch (Fig. 21) it is important 
to note that all the main straight outlines are drawn 
along three principal directions, one being exactly ver- 
tical and the other two making an angle of 120° with 
the first one. This method of representing objects 
approaches very closely to the natural appearance of 
any object to the eye and it is known as the Isometric 
Projection. It is used a great deal in cabinet-making, 
sheet-metal work and all similar cases where all the 
three directions are represented in the same view. 

The pole pieces in Fig. 21 are in each case drawn 
at right angles to the interior of the framing, and 
the drawing is then completed by adding the smaller 
details and by proper shading so as to indicate the 
light shining from the lower right-hand corner. We 
must also consider here the shadows thrown by one 
part of the machine upon the other, as well as the 
shadows thrown by these parts upon the base of 
support or the other objects in the Immediate vicinity. 
Every portion of this sketch must be gone over care- 
fully several times by the aid of the eraser and pen- 
cil until each one is neat and accurate and the whole 
drawing gives the correct impression of the appear- 
ance of the machine. 

Fig. 22 is a somewhat similar sketch of a special 
electrical fitting Intended particularly as an Illustra- 
tion for an advertisement showing the main points of 
connections and a portion of the Interior arrangement 
for contact. 



FREE HAND DRAWING 



33 



The main body of the fitting (see Fig. 22) is made 
up of a cylindrical receptacle provided with circular 
base having four projecting pieces attached to it for 
support and also for making the necessary connections. 
The top of the fitting being open and of circular shape 




FIG. 22. 

is indicated by means of two ellipses, the distance be- 
tween these curves corresponding to the thickness of 
the wall of the appliance. Inside of this hollow cylin- 
der there is a portion of another ellipse shaded very 
heavily to show the metal connection visible at that 
point. 



34 FREE HAND DRAWING 

Special stress is laid upon the connection lugs and 
screws, since these form one of the features of advant- 
age of this particular electrical specialty, and these are 
shown very prominently and shaded with particular 
care to bring out these parts clearly. The outline of 
the base is made partly cylindrical and partly rectang- 
ular according to the location of the particular part, 
since the space between the four projecting pieces is 
made up of arcs of a circle of a radius somewhat larger 
than the outside radius of the top portion of the fit- 
ting. 

The shading in Fig. 22 is very simple, since the whole 
figure is symmetrical about a common vertical axis, 
and all the shade lines are practically all vertical. 

The lamp drawn in Fig. 23 illustrates the method of 
drawing an object entirely without any sharp outlines 
but merely by the aid of shade and shadow lines. 

For this sketch we have to make use of the pencil- 
compass as well as of the straight edge, but any lines 
drawn in that manner are used merely as guide lines 
and are later erased in the course of shading, so that 
the whole sketch when finished has no sharp lines 
but very carefully drawn shade lines of varying 
strength and spacing according to the amount of light 
or shadow we wish to indicate at any particular point. 
Such a method of free-hand drawing can be acquired 
by the aid of frequent exercise with models and objects 
placed at different positions with respect to an actual 
source of light. 

Another type of technical illustration used a great 
deal for catalogues is shown in Fig. 24, which is a 
rough sketch of a certain type of mast jib-crane show- 
ing its general construction, method of support and its 
relative position with respect to other objects. 

The lines are drawn with the aid of a rule, and the 
principles of isometric projection are employed here so 
as to show the view of the steel members making up 



FREE HAND DRAWING 



35 



the framing and the appearance of its upper and lower 
supports. The traveling trolley riding on top of the 
channel frame is indicated by its circular wheels and a 
few main lines of the casting that forms the carriage of 
the trolley. The hoisting chain, block and hook are 
indicated roughly, giving none of their details, but 
presenting the appearance of the complete equipment 
in a general way. 




FIG. 23. 



Such sketches are usually supplemented with notes 
giving the names and the directions for each part of 
the mechanism as well as the principal dimensions, so 
that by the aid of such a rough free-hand sketch, we 
have a clear idea as to the operation of the machine 



36 



FREE HAND DRAWING 







FIG. 24. 



FREE HAND DRAWING 37 

and the* space it would require, giving us enough data 
to enable us to make an exact working drawing of the 
same machine, to scale. 

The shading of this drawing is similar to those dis- 
cussed above, including the shadow lines at the lower 
support of the crane. 

In all the above types of technical illustrations our 
first object must be borne in mind, and that is to pre- 
sent the sketch in such a manner that the reader can 
get a clear idea of the general construction as well as 
the appearance of the particular machine or equip- 
ment which is illustrated so that the main features 
could be grasped at once without requiring any long 
description by means of text. An illustration of this 
kind if neat and accurate will convey more information 
at a glance than volumes of writing and it will be 
found of great value to both the designing engineer 
and the sales manager of the machine. 



CHAPTER VL 
Technical Sketching. 

The practical application of the principles of free- 
hand drawing to purely engineering work is espe- 
cially important in making rapid sketches of either 
objects existing on a particular job to be investigated 
or of work to be contemplated in the future. There 
are many occasions in the daily experience of every 
engineer or any man connected with engineering work 
when he is called' upon to represent an object in its 
correct relation to other things^ making a rough out- 
line and giving all the necessary dimensions or other 
notes of information. This is usually required to be 
made in a short period of time under circumstance 
which would not permit of the elaborate use of a 
board, T-square or drawing instruments so that the 
drawing is made absolutely free-hand, with only a 
pencil and a scrap of paper, and with no means for 
supporting the sketching paper except an occasional 
back of a book or a wooden board. There are mo- 
ments snatched v/hi\e traveling on the train when an 
idea presents itself to the engineer about the job, 
which he wishes to preserve at once for future de- 
velopment. Then he has to use any chance scrap of 
paper such as a back of an envelope and a stub of a 
pencil to illustrate his idea with an accurate sketch, 
which would be intelligible to himself and others when 
the occasion arrives for making use of it. In all such 
cases of emergency the modern engineer must train 
himself to make these sketches rapidly, yet as neatly 
and accurately as the occasion might require. 

In the first place it is very important for every 
technical man to have with him as part of his daily 



FREE HAND DRAWING 



89 






,^^ 




40 FREE HAND DRAWING 

equipment some kind of a memorandum book of a 
size convenient to be carried in the pocket, yet suffi- 
ciently large to allow enough space for notes and 
sketches. A loose-leaf form is to be recommended 
since the leaves can later be thrown away after they 
have been copied in a more permanent form and they 
can then be replaced by new ones at very small ex- 
pence. 

It is preferable to have at least part of this note- 
book made of cross-section paper ordinarily used for 
figuring, since these equal divisions wuU then serve 
as a rough guide for straight lines and for the gen- 
eral symmetry of the sketches, and this paper can 
also be used to greater advantage in making compu- 
tations. 

The sketches can be made either representing the 
objects as they actually appear to the eye as illus- 
trated in the previous chapters, or we can make use 
of the ordinary rules of projection^ which allows the 
accurate representation of those views of the body 
with which we are concerned leaving out all other de- 
tails which would not add any information. 

To illustrate some of the typical sketches made on 
the job, let us examine the rough outline of a piping 
connection shown in Fig. 25. At a glance we can 
note that this pipe has two right-angular turns, one 
from vertical to the right and then from the right to 
the front. The first turn is accomplished by means 
of a long-radius elbow, having a radius of 3 feet, and 
the second turn is made by means of a standard elbow 
its forward flange facing the observer and having 12 
bolts spaced evenly around a 10|-inch bolt-circle. 
These two elbows are connected by means of a 12- 
foot-straight piece, and all the connections are made 
by means of flanged joints bolted together. We have 
here the main dimensions of these fittings, the size of 
the pipe, its distance from a wall and the height of 



FREE HAND DRAWING 



41 




42 FREE HAND DRAWING 

the horizontal run above the first floor of the build- 
ing. This amount of information seems to be suffi- 
cient for building the whole portion of the piping, for 
locating it correctly to scale on any drawing or for 
reporting the condition as it exists to the man in the 
office who is interested in that particular information. 
Such a drawing is a correct picture of the appearance 
of the piping as well as a projection drawing since it 
is the front elevation of the pipe with its lower end 
cut off and the front portion disconnected. Such a 
sketch can easily be made in 5 or 10 minutes. The 
usual procedure is first to draw the whole view of the 
piping in the right proportion, not attempting to make 
perfect lines or curves but using enough care so that 
the general appearance conveys a clear idea of the 
object. A little shading will greatly help the impres- 
sion and should not be omitted in any of these sketch- 
es. Then the measurements that would be required 
are decided upon and the proper lines and arrow- 
points are drawn in so as to be certain that none of 
the measurement would accidentally be omitted. 
Great care must be taken to place the arrow-points so 
as to clearly indicate the points between which the 
measurements are taken. Then the actual measure- 
ments are made and are noted as fast as they are ob- 
tained, none of them being kept in mind for any 
length of time before being noted, thus avoiding the 
chance of forgetting them or confusing them with 
others. Each dimension should be carefully checked 
by adding or substracting from some other point of 
reference, such as a wall, column, etc. After all the 
measurements are noted and checked, the whole job 
must be given a thorough inspection and all informa- 
tion relating to the purpose on hand should be clearly 
covered by notes on the same sketch unless these 
notes are so large as to require a separate page. 
This rough and ready method of drawing is used 



FREE HAND DRAWING 43 

not only for engineering objects that are already in 
existence, but also for designing things that exist only 
in the mind of the draftsman. This is done so as to 
represent the idea rapidly in a more concrete form 
before attempting to draw it to scale. Fig. 26 repre- 
sents such a rough design of a cast iron Y-branch as 
it appears to the draftsman before the actual detailed 
drawing is made. It contained one full longitudinal 
section of the fitting and a partial section showing all 
the important features of the piece and giving only 
the principal dimensions for preliminary computa- 
tions. After these dimensions are checked and some- 
what modified by computation, then the same piece 
can be laid out to scale and it can be detailed to suit 
the particular requirements. These preliminary 
sketches are very valuable for future reference and 
should be carefully filed for permanent record. In 
Fig. 27 we have a case of structual detail where the 
notes are more valuable than the dimensions, since 
in this case the parts of the steel structure are made 
of standard material and as long as the size of the 
I-Beam angle or channel is noted we can easily find 
all their other, dimensions or properties from any 
handbook of structual steel shapes. The two im- 
portant dimensions that would be essential in such 
work are the horizintal spacing of the 12-inch I-beams 
and height of the concrete slab above the top of the 
beams. This sketch is not complete in itself since it 
does not give the length and arrangement of the 
above members in plain view or in horizontal plane, 
but it is sufficient for the purpose of illustrating the 
construction of a particular section of the building. 

In making sketches of electrical wiring such as 
shown in Fig. 28, we hardly need any dimensions, un- 
der ordinary circumstances, except the size and loca- 
tion of the switchboard panel. The purpose of this 
sketch primarily is to show the relative location of 



u 



FREE HAND DRAWING 






^-1 




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^5< 


>-l 


of- 


^^ 


.X 


>^ 


v^ 


o 


ot 



00 







"I 


VVi 


> 


s 


l> 






L V 






\^V^ 






^ 


1 




It 


^ 




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v; 






1 


^ 






J 


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f 


^ 


^ 




•vJ 


5i< 







FREE HAND DRAWING 



45 



I /•*' 



5 '-6 



■^ 



From ^ Col 26 




Fironx 
SecanJaftes 



LiM 



Bo'Ck qS fhne./ 

-i^O" FfotnEast 

Wall. 

iTlahbk SUh 

Z'/f"Th.ick 

heveleJ air 



7^2 



// 



FIG. 28. 



46 FREE HAND DRAWING 

instruments, switches and fuses on the board and 
their connections on the panel as well as to the main 
incoming and outgoing conduit lines. It is custom- 
ary in all such electrical sketches to distinguish be- 
tween the heavier and lighter wires or cables by 
means of correspondingly heavier or lighter lines on 
the drawing. The panel is usually sketched from the 
rear showing all the back wiring but also outlining 
the instruments, switches and all other equipment in 
their proper places, although they are actually all 
placed in the front part of the panel. The notes give 
the location of the switchboard and the character of 
the material and general construction as indicated in 
the sketch. 

It might be proper here again to emphasize the 
necessity for training the powers of observation so 
there should be very little difference between ''look- 
ing" and ''seeing." 

This power of observing things is a part of the re- 
quirements of the modern engineer and it goes hand 
in hand with his ability to make good free-^hand 
sketches. In fact, we might say^ that by making a 
great number of free-hand drawings the engineer gets 
the benefit of a valuable training as an observer, and, 
on the other hand, by learning proper methods of 
observation the engineer becomes an expert in mak- 
ing accurate !free-hand sketches besides being gen- 
erally of greater use in the other duties of his profes- 
sion. 



CHAPTER VII. 

Engineering Drawing. 

By Joseph G. Branch. 

In practically all branches of engineering work, 
drawing is made of extensive use as a medium of 
expression for the interchange of ideas. So indispens- 
able is drawing in this connection that it has virtually 
become the engineers' language, without which they 
would have great difficulty in making themselves un- 
derstood. Whenever a piece of construction is to be 
undertaken, no matter whether it be a huge building 
or a tiny mechanism smaller than a watch, drawings 
are practically always used to convey to the builder 
or mechanician the ideas and wishes of the designer. 
The day of "cut and try*' in engineering construction 
has gone, and the more exact modern methods have 
come to stay. 

This necessity for drawings in connection with all 
kinds of engineering work has had the effect of 
standardizing methods of drawing. This has the ef- 
fect of making the ''language of drawing'' more readily 
and easily understood by all who use it. Since all 
engineers use the same methods in their drawing 
there can be no doubt as to what is meant by a par- 
ticular drawing, assuming of course that it has been 
properly and correctly done. 

In general there are two methods which are recog- 
nized in connection with drawing for mechanical 
purposes. These are: 1. Perspective Drawing, and 
8. Mechanical, or Projection Drawing. 

In perspective drawing an oibject is drawn as it ap- 
pears to the eye, and not necessarily as it really is. 
The fact that bodies do not appear to the eye as they 



48 FREE HAND DRAWING 

really are is one of universal experience. The rails 
on a track appear to come closer together as they 
recede from the observer, but wc know that they are 
always parallel. Houses seen at a distance appear to 
be smaller than others nearer at hand, although as a 
matter of fact just the reverse may be the case. So 
in perspective drawing this is always kept in mind, 
and the object drawn as it seems to be. 

The value of this kind of drawing depends upon the 
fact that it conveys to the mind of the observer an 
idea of what the object shown really looks like. Pat- 
ent Office drawings, presented in connection with an 
application for a patent, are frequently made in per- 
spective. This conveys to the mind of the examiner 
a definite picture of the object in question, similar to 
what would be obtained from a model. 

But when an object is to be constructed it is quite 
evident that the mechanic who is to do the work wdll 
need something more than a perspective drawing. 
He must know what the object in question is really 
like in order that he may be able to make it correctly. 
So for this purpose a mechanical or projection draw- 
ing is used, which shows the object as it actually is. 
To a person who is inexperienced in the use of such 
a drawing, it will often look very unlike the object 
which it represents. But experience with mechanical 
drawings very soon develops in a person the ability 
to form a mental picture of what the object is like. 
In other words he learns to *'read'' the drawing, and 
so get the information which it contains. 

The Mechanical Draftsman. 

The necessity for drawings which show what an 
object is really like, so that it may be made correctly 
by one who has never seen anything like it before, 
has produced the profession of the mechanical drafts- 
man. It is the function of the draftsman to make all 
the drawings necessary for the construction of the 



FREE HAND DRAWING 49 

object in question. Suppose for example that some 
special kind of automatic machine is to be built, noth- 
ing like it ever having been made before. The drafts- 
man will usually make what is known as an ''assem- 
bly drawing" of the machine, which shows the entire 
mechanism completely assembled. In case such a 
complete drawing is impracticable or undesirable for 
any reason, he will make drawings which show the 
essential parts of the machine, put together or as- 
sembled as they be in the completed object. 

But the draftsman must do more than this. He 
must make what are known as '^detail'' or "working" 
drawings, for the use of the mechanics who are to 
make the various parts of the machine. Such work 
is usually spoken of in the drafting room as "detail- 
ing," and consists in making a separate drawing of 
each individual piece or part which goes into the 
completed machine. Of course if there are two or 
more parts exactly alike, only one drawing is re- 
quired, and then the draftsman simply puts a note on 
his drawing thus: "Make Two,'' or "Make Four," 
or whatever the desired number may be. 

Usually the draftsman who makes the detail draw- 
ings is not the one who made the assembly drawings, 
although in some cases both drawings may be made 
by the same man. In case a different man makes the 
details, he must work from the assembly drawings, 
and hence the latter must be complete and correct if 
the details are to be correct. 

When the drawings go into the shop where the ma- 
chine is to be built, the pattern-maker, the machinist, 
and other mechanics wilJ work from the detail draw- 
ings, because they show exactly what the various 
parts are like. An assembly drawing may or may 
not accompany the detail drawing into the shop. If 
it does, the mechanic can see where the piece that he 
is making is to go in the finished machine. But if 



60 FREE HAND DRAWING 

there is no assembly drawing he makes the pieces as 
they are shown in the details, and his responsibility 
ends there. If the pieces fail to fit properly when the 
machine is finished, the error is in the drafting room, 
not in the shop. 

After all the parts are made they go to the as- 
sembling shop, where the machine is put together. 
Here the assembly drawing is of importance because 
it shows how the various parts go together. The 
machinist who assembles the machine will therefore 
be supplied with the assembly drawing, and with all 
the parts at hand, properly made, he turns out the 
finished machine. 

The Designer. 

If the machine which we have been considering is 
something which has never been made before, it is 
quite proper to ask where the draftsman received his 
information, which enabled him to make the original 
designs. He must have had something to work from, 
because the mechanism to be built must have had an 
origin somewhere. The answer is that the machine 
originated with the designer. Having in mind a cer- 
tain kind of work which he wished the proposed ma- 
chine to do, he set out to devise a mechanism which 
would do it. It IS of course unlikely that the first 
idea which occurs to him will prove to be the desired 
solution, so he tries one after another until the best 
one is finally discovered and decided upon. 

In some engineering offices the designer and the 
draftsman are one and the same person, but in the 
larger concerns the tendency is to separate the work, 
having the designing done by one man, and the draft- 
ing by another. If a man is a designer only, the tools 
with which he works are simply a pencil, an eraser, 
and a pad of paper. When he sits down to design 
his machine, and a particular mechanism occurs to 



FREE HAND DRAWING 51 

him as a possible solution of ihis problem, he sketches 
it out free-hand, so that he may have an opportunity 
to consider it more carefully. If it looks good, he 
proceeds to develop the idea, sketching it in as the 
machine groves in his mind. Certain changes may 
seem desirable at times, and he simply erases part of 
what he has drawn and sketches it again according to 
the new idea. Finally the complete design is decided 
upon, and sketched on his drawing pad, although of 
course it is all very rough and unfinished, because 
done free-hand, that is, without the use of instru- 
ments. 

Then the designer calls in the draftsman, shows him 
the sketches and explains the idea to him. The 
draftsman then makes the finished mechanical draw- 
ings from the designers sketches. Of course the 
draftsman must also be somewhat of a designer him- 
self, because the designer's sketches will probably 
cover only the main features of the machine, leaving 
many of the details to be worked out by the drafts- 
man. So it often happens that the draftsman will 
make free-hand sketches of a number of different 
parts of the proposed machine, before he decides defi- 
nitely on the proper shape and size. After the gen- 
eral design and many of the details have been fixed 
in his mind, he will then take up his draftsmans' in- 
struments and proceed to make the mecanical draw- 
ings. 

It should be evident from the foregoing that no 
man can hope to become a successful draftsman or 
designer if he has no knowledge of free-hand draw- 
ing. Such drawing forms the basis for most me- 
chanical drawings, because the free-hand drawing is 
what the draftsman must work from when making his 
finished drawing. Every new machine, almost with- 
out exception^ has its origin in a free-hand drawing. 



52 FREE HAND DRAWING 

and hence the latter is the beginning of all engineer- 
ing drawing. 

After free-hand drawing has been mastered, it will 
be found that mechanical drawing consists in making 
the same kind of a drawing, but making it more neat- 
ly and accurately by means of instruments. Hence 
a study of free-hand drawing is very essential for 
anyone who wishes to become a mechanical drafts- 
man. It is, in fact, a long step in the right direction, 
and will make the understanding of purely mechanical 
drawing very much easier. 



Examination Questions 



54 EXAMINATION QUESTIONS 

FREE HAND DRAWING. 

Directions. 
No scale or ruler must be used in any free-hand 
drawings. Only a soft pencil and eraser. 

LESSON ONE. 

Examination Questions. 

1. What are the two principal kinds of sketches em- 

ployed in engineering work? 

2. What is the first thing to learn in free-hand draw- 

ing? 

3. Must the eye or the hand be first trained? 

4. Are free-hand sketches drawn to a correct scale? 

5. How is the pencil held and the line first drawn? 

6. What is the most important element of free-hand 

drawing? 

7. Explain how you would draw a horizontal line? 

A vertical line? 

8. How would you draw an angle? A rectangle? 

9. How a square? An equilateral triangle? 

Exercises. 

1. Draw one hundred straight lines. One hundred 

vertical lines. 

2. Draw a horizontal line one and one-half inches long. 

A vertical line the same length. 

3. Draw five right angles. Five 45 degree angles. 

Five 15 degree angles. Five 10 degree angles. 

4. Draw a triangle. An equilateral triangle. 

5. Draw a rectangle three inches long and two inches 

wide, 

6. Draw a square two by two inches. 

7. Draw a triangle with a base of one and three-quar- 

ter inches. 



EXAMINATION QUESTIONS 55 

LESSON TWO. 

Examination Questions. 

1. Which lines are easier to draw free-hand: straight 

or curved? 

2. Give several ways of drawing a circle without the 

use of a compass. 

3. Name the two principal axes of the ellipse. 

4. Give the method for finding the two foci of the 

ellipse. 

5. Which is the easiest way to draw an ellipse free- 

hand ? 

6. How is a cylinder represented by a free-hand 

sketch ? 

7. What is the method used in shading an object 

drawn free-hand? 

8. How would you draw a square pyramid? A hex- 

agonal pyramid? 

9. How would you draw a rectangular prism ? 

Exercises. 

1. Draw a circle by the aid of a silver dollar. 

2. Draw a circle by turning the paper around the in- 

dex finger. 

3. Draw a circle 3 inches in diameter free-hand ; 4 

inches; 5 inches. 

4. Draw several concentric circles (inside one another, 

from the same center). 

5. Draw 3 circles of unequal size tangent to one an^ 

other (touching one another). 

6. Draw an ellipse having a major axis of 3 inches 

and a minor axis of lyi inches; 4 inches by 1>4 
inches. 

7. Draw a cylinder lying on its side with one of its 

ends exposed to view at an angle. 

8. Draw several (at least three) combinations of cyl- 

inders, pyramids and prisms and shade them 
properly. 



56 EXAMINATION QUESTIONS 

LESSON THREE. 

Examination Questions. 

1. Do objects appear to the eye exactly as they really 

are in nature ? 

2. In drawing a group of objects, which one should be 

taken up first. 

3. What determines the distribution of shading on 

a free-hand sketch of any object? 

4. What is the difiference between shading and 

shadows ? 

5. How does the angle of an object determine the im- 

pression of its length to the eye ? 

6. What is the appearance of a circle placed in a plane 

parallel to the observer? At an angle to the ob- 
server? At right angles? 

7. How can an object be represented without sharp 

outlines? 

8. What kind of lines are used in representing an ob- 

ject by shading it? 

Exercises. 

1. Draw a combination of a hexagonal prism and a 

cone in three different positions. 

2. Draw a cube at an angle and use no sharp outlines, 

but make up the figure by proper shade lines. 

3. Draw a combination of a cylinder, cone and sphere. 

4. Draw a cone tilted towards the observer at three 

different angles. 

5. Show three sections of a cone. 

6. Show three sections of a square pyramid. 



EXAMINATION QUESTIONS 57 

LESSON FOUR. 

Examination Questions. 

1. What is meant by perspective drawing? 

2. How many vanishing points are to be considered 

in drawing an object in perspective? 

3. How are equal distances between similar points af- 

fected by the direction of the vanishing lines ? 

4. How would you draw objects with curved parts 

in perspective? 

5. How are vertical distances represented in per- 

spective drawing? 

6. How would you draw an outline of a street in per- 

spective ? 

Exercises. 

1. Draw an outline of a train in perspective. 

2. Make a mechanical layout or plan of some manu- 

facturing plant. 

3. Show the same plant in perspective, in sharp out- 

line. 

4. Shade the sketch made in exercise 3. 

5. Copy a sketch in perspective from a catalog. 

6. Make the same sketch from memory. 

LESSON FIVE. 

Examination Questions. 

1. What branch of drawing is most frequently used 

for preparing technical illustrations? 

2. What is the difference between an illustration and 

a working drawing? 

3. How can an illustration be prepared accurately 

without looking at the actual object or a model? 

4. What are the principal lines of direction in an iso- 

metric drawing? 

5. What use is made of shading in technical illus- 

trations ? 

6. What is meant by guide-lines as distinguished from 

prominent lines and shade lines? 



58 EXAMINATION QUESTIONS 

7. What type of drawing is best to be used for show- 

ing the main features and dimensions of a ma- 
chine? 

8. What additional information must be supplied to 

make a technical sketch of a machine complete ? 

Exercises. 

1. Make a free-hand sketch of your parlor lamp, or 

some gas or electric fixture. 

2. Copy a sketch of some pipe fitting from a catalog. 

3. Draw the sketch of the same pipe fitting from mem- 

ory. 

4. Make a free-hand drawing of a small pump by ob- 

serving it in 3^our own work. 

5. Add enough dimensions to your sketch to supply 

all the information for a prospective buyer. 

6. Make a study of three or more catalog illustrations 

of a technical nature and see if you can copy 
them from memory. 

LESSON SIX. 

Examination Questions. 

1. Name several occasions when rapid technical 

sketching is required by an engineer. 

2. What material is required for technical sketching? 

3. What kind of drawing is used for technical sketch- 

ing : mechanical, isometric or perspective ? 

4. What method would you use in making a technical 

sketch of a machine or structure in place? 

5. How is technical sketching used by the designing 

engineer and draftsman? 

6. How would you make a sketch of a structural steel 

or concrete structure ? 

7. How would you make a sketch of an electrical 

switchboard or wiring scheme? 

8. What is the difference between "looking'' and "see- 

ing"? 



EXAMINATION QUESTIONS 

Exercises. 

1. Make a sketch of some part of pipe in a steam power 

plant where you are working. 

2. Design a piping system for heating a garage and 

make the necessary free-hand sketches. 

3. Copy a mechanical drawing of a building section 

by the free-hand system. 

4. Draw up a detail of a part of a machine from obser- 

vation or memory, and put in all necessary notes 
and dimensions. 

5. Draw a free-hand sketch showing the wiring of a 

simple switchboard. 

6. Make a sketch showing wiring of an automobile ig- 

nition system. 

LESSON SEVEN. 

Review Questions. 

1. What is the importance of free-hand drawing for 

the practical engineer? 

2. What is the importance of rapid sketching for the 

designer? 

3. How are machines originally designed? 

4. What is the difference between an assembly and a 

detail drawing? 

5. What instruments are essential for mechanical 

drawing? 

6. What materials are required for free-hand sketch- 

ing? 

7. Why is it not practicable to make all preliminary 

studies by means of scaled mechanical drawings ? 

8. What studies are required to enable the student 

to be trained as a designer? 



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